Cutter tool retained by spring detent



Nov. 3, 1964 s. E. PRocToR CUTTER TOOL RETAINED BY SPRING DETENT v IFiled April 12, 1962 Iuveunog V SIDNEY PiouroL ma/'14 M,%

ATTaRuers United States Patent 3,155,428 CUTTER TOOL RETAINED BY SPRINGDETENT Sidney Ernest Proctor, High Wycombe, England, assignor to AustinRoy and Company Limited, High Wycomhe, England, a British company FiledApr. 12, 1962, Ser. No. 186,987 Claims priority, application GreatBritain, Apr. 13, 1961, 13,386/ 61; May 11, 1961, 17,286/ 61 3 Claims.(Cl. 299-92) This invention comprises improvements in or relating totool-carrying chains.

In tool-carrying chains such, for example, as the chains used in coalcutters for carrying the picks which cut the coal, it is necessary fromtime to time to change the picks, either by reversing them in the toolboxes so that the chain will cut in the opposite direction or bysubstituting fresh sharp picks for old blunted ones. The picks arenormally held in the pick boxes by set screws gripping the sides of theshanks of the tools and the operation of changing all the tools in achain takes a considerable time. This is particularly true with a coalcutter chain because of the cramped conditions under which the Workoften has to be performed, and various means have been proposed fromtime to time to make the changing of tools quicker and easier, but thesefrequently involve complication, or have proved unsatisfactory inservice under the hard conditions which are involved with a coal cutter.It is an object of the present invention to provide an improved device.

The present invention comprises a tool-carrying chain having removabletools held by their shanks in toolboxes carried by the chaincharacterised by the fact that the shanks are retained in the tool boxesby means of a spring detent member which yields to permit easy insertionof the shank but resists withdrawal.

In a preferred construction the detent members take the form ofpart-rings of spring metal each let into a recess in the side of one ofthe two elements it is to hold together (shank and tool-box) so as toproject somewhat beyond the side and the other elements each have asurface facing the detent member which is inclined so as to overhang thedetent member when the two elements are fitted together.

The following is a description, by way of example, of certainconstructions in accordance with the present invention, reference beingmade to the accompanying drawing in which:

FIGURE 1 is a vertical section through a tool-box showing a tool held inplace by a spring-ring type of detent member;

FIGURE 2 is a view similar to FIGURE 1 but showing the tool shank in theact of insertion;

FIGURE 3 is a similar view of an alternative construction;

FIGURE 4 is a detail of a spring detent member shown in FIGURE 3;

FIGURE 5 is a detail showing a pick-removing-tool.

The general construction of the coal cutter chain may be any desired andthe links or some of them carry projecting tool-boxes in the usual wayone of which appears at 11, FIGURE 1, projecting from a chain-link 12.These boxes 11 are pierced with rectangular openings 13 to receive theshanks 14 of cutter picks 15. Each pick shank 14 is bored through fromside to side near the rear edge of the shank, with a hole 16 which islarge enough to be partly open to the rear edge. In this hole there isfitted a spring-ring 17. The ring 17 is made of fiat spring steel stripof the same width as the shank 14 and it is coiled into a circle alittle larger than the internal diameter of the hole 16 in the shank sothat it has to be compressed to get it into place. The ring extendsaround somewhat "ice less than one complete turn and it has a rootportion 18 which is bent radially outwards. This root portion fits intoa slot 19 extending from the hole.16 in which the spring is fittedwithin the shank 14, in a direction parallel to its rear edge. In orderto produce the hole 16 with the slot 19 extending from it, it isconvenient to bring the hole to its final shape by broaching. It will beappreciated that, owing to the location of the hole 16, when thespring-ring 17 is in place in the shank one side of the ring 17 projectsbeyond the plane of the rear edge 20 of the shank 14 and if the shank ispushed into the rectangular aperture 13 in the tool-box the spring-ring17 Will have to be compressed to enable it to go in, but the directionof the force exerted by the top corner of the tool-box at theshank-receiving opening is upward and inward, as shown by arrow A,FIGURE 2, and this is a direction in which the exertion of force tendsto press the spring-ring in easily, as shown by the chain line position17a.

The tool-box 11 is drilled through in a fore and aft direction, that isto say, parallel to the length of the chain, with an opening 21 whichintersects the aperture 13 for the reception of the shank 14. When thetool shank 14 is pressed into place the spring-ring 17 will register,according to whether the tool is facing forwardly, as shown in FIGURE 1,or rearwardly, with either the forward portion 22 or the rearwardportion 23 of this hole. In each portion of the hole there is a hardenedsteel plug 24 which is welded in place and which has an inner face 25 tobear on the spring-ring 17. The inner faces 25 of the two plugs areinclined in such a direction that the parts of the plugs which arenearest the top of the tool-box overhang the lower parts and one of themoverhangs the spring-ring 17 when the shank 14 is pushed home, as inFIGURE 1. The spring-ring then bears against the inclined face 25 andholds the tool in place. If the tool is reversed to face the other waythe spring ring 17 will bear against the inclined face of the otherplug.

The insertion of the tools is easy for the reason above stated, namely,that the pressure exerted by the corner of the tool-box on thespring-ring 17 is in the direction which tends to close it easily, itbeing noted by reference to FIGURE 2 that the free end of the projectingfree ended portion of the ring 17 is normally spaced from the upper edgeof recess 16 to avoid interference with upward and inward deflection ofsaid portion into the recess. Withdrawal of the shank of the toolhowever is resisted by pressure of the inclined face 25 of the plug 24on the ring 17 and withdrawal is more difiicult because the direc tionof the force is as shown by arrow B and not only is this force downward,it is aimed below the centre of the ring 17, which is therefore pressedagainst the bottom of hole 16 and is supported against contraction morestitlly. The tool 15 is therefore securely held in place, thespring-ring 17 constituting a detent member which resists withdrawal.However, if enough force is exerted in the outward direction theresistance of the ring 17 to contraction will be overcome and the ringwill be closed by the action of the inclined face 25 so that the toolcan be withdrawn.

For the purpose of withdrawing the tool the head of the tool 15 outsidethe tool-box is provided with a transverse opening 26 and the end of alever 48 (FIGURE 5) can be inserted in the opening, the lever having aheel 49 to rest on the tool-box 11 beside the tool and afford.

leverage by which the latter may be prised out of its seating in theshank. By use of the lever all the tools may be rapidly prised outwhenever desired. If they require to be reversed they can be reinsertedthe other way round and the detent members in their shanks will thenco-opcrate with the inclined faces of the plugs in the opposite side ofthe shank aperture 13 from that which contained the plug they engagedbefore. If the tools need to be changed, of course, it is an equallysimple matter to insert the new tools.

It will be seen that there are no set screws involved in thisconstruction and no loose parts to come adrift or get lost and thenumber of parts for the complete chain is reduced to a minimum.

Referring now to FIGURES 3 and 4, a spring-part-ring 27 is used as adetent member, such as is described above in connection with FIGURES 1and 2, but instead of being anchored in the shank of the tool by a rootportion 18 located in a slot extending from the housing-hole 16 in theshank 14 close to the upper end of the shank, the anchorage is locatedfurther round the housing-hole (anticlockwise in the figure), at about45 below the centre line of the housing-hole 16, and the spring-ring 27is little more than a semi-circle. The anchorage is a small drilledholeZS in the shank, the side of which breaks out into the hole 16 andto keep the ring 27 pressed against the lower side of hole 16 it has atail 29 above the anchorage along part of the interior surface of thehole 16.

The ring 27 is constructed as shown in FIGURE 4, with a curl at 30 tofit the hole 28 and the extension 29. passing up from the end of thecurl through an aperture 31 in the spring-ring. The upper part of hole16 is broached out to a rectangular shape at 32. The tool-box 11 isdrilled as before and plugged, but the plugs, shown at 34, have asharper inclination at 33, where they are intended to overlie the ring27. The operation is similar to that of FIGURES 1 and 2.

I claim:

1. A cutter tool and tool box assembly comprising: a cutter tool havinga shank, an elongated tool box having an elongated socket open at itsupper end to receive said shank, said shank being disposed in saidsocket and formed with a recess opening outwardly through a side surfaceof the shank transversely to the length thereof, a detent membersupported within said recess and having a resiliently flexible freeended portion arcuately curved in a plane parallel to the length of saidshank and projecting from said recess beyond said side surface of theshank, a retaining cam in said socket having a cam surface which isinclined with respect of the longitudinal axis of the socket and which,when the shank is home in the socket, overhangs said detent member andis engaged thereby, the free end of said portion being directed towardsaid open end of the socket and spaced from the upper edge of saidrecess to permit comparatively easy upward and inward yielding of saidportion into the recess, said detent member normally contacting thelower edge of said recess to offer comparatively greater resistance toflexing of said portion into the recess by the exertion of downwardlyand inwardly directed forces thereon.

2. An assembly as claimed in claim 1 wherein the detent member comprisesa part-ring of spring metal and the transverse recess in the shank fitsthe extension of the part-ring with the exception of said free endedportion of the ring which projects from the surface of the shank, saidpart-ring having a root portion, said tool box being formed with agroove opening into said recess and receiving said root portion tolocate the part-ring in the recess.

3. An assembly as claimed in claim 1 wherein said inclined cam surfacein the socket is formed on a hardened plug fixedly housed within a boreopening through said tool box into the side of the socket.

References Cited in the file of this patent UNITED STATES PATENTS2,916,275 Bruestle et al Dec. 8, 1959 2,965,365 Krekeler Dec. 20, 19603,021,124 Bowen Feb. 13, 1962

1. A CUTTER TOOL AND TOOL BOX ASSEMBLY COMPRISING: A CUTTER TOOL HAVINGA SHANK, AN ELONGATED TOOL BOX HAVING AN ELONGATED SOCKET OPEN AT ITSUPPER END TO RECEIVE SAID SHANK, SAID SHANK BEING DISPOSED IN SAIDSOCKET AND FORMED WITH A RECESS OPENING OUTWARDLY THROUGH A SIDE SURFACEOF THE SHANK TRANSVERSELY TO THE LENGTH THEREOF, A DETENT MEMBERSUPPORTED WITHIN SAID RECESS AND HAVING A RESILIENTLY FLEXIBLE FREEENDED PORTION ARCUATELY CURVED IN A PLANE PARALLEL TO THE LENGTH OF SAIDSHANK AND PROJECTING FROM SAID RECESS BEYOND SAID SIDE SURFACE OF THESHANK, A RETAINING CAM IN SAID SOCKET HAVING A CAM SURFACE WHICH ISINCLINED WITH RESPECT OF THE LONGITUDINAL AXIS OF THE SOCKET AND WHICH,WHEN THE SHANK IS HOME IN THE SOCKET, OVERHANGS SAID DETENT MEMBER ANDIS ENGAGED THEREBY, THE FREE END OF SAID PORTION BEING DIRECTED TOWARDSAID OPEN END OF THE SOCKET AND SPACED FROM THE UPPER EDGE OF SAIDRECESS TO PERMIT COMPARATIVELY EASY UPWARD AND INWARD YIELDING OF SAIDPORTION INTO THE RECESS, SAID DETENT MEMBER NORMALLY CONTACTING THELOWER EDGE OF SAID RECESS TO OFFER COMPARATIVELY GREATER RESISTANCE TOFLEXING OF SAID PORTION INTO THE RECESS BY THE EXERTION OF DOWNWARDLYAND INWARDLY DIRECTED FORCES THEREON.